应用改进的水热反应法制得粒径小且分布均匀的L iFePO4颗粒,煅烧时加葡萄糖形成包覆碳.XRD、SEM和充放电测试表明,该材料粒径约200 nm,颗粒的尺寸分布比较均匀,具有3.45 V的放电平台,放电容量最高达到140 mAh/g,循环到第40周容量仅衰减2.1%.详细讨论了如何有效调控L iFePO4的粒子尺寸以及包覆碳对其电化学性能的影响.
LiFePO_(4) was synthesized by means of hydrothermal reaction,in which PVA acts as disperser and glucose as carbon source.The samples were characterized by X-ray diffraction,scanning electron microscopy and electrochemical measurement.SEM results show that the sample is homogeneously composed of grains with a particle size of ca.200nm.In the charge/discharge test,the products exhibited a 3.45V discharge voltage plateau and a maximum specific capacity of 140mAh/g.After 40 cycles,its capacity only declined by 2.1%.Besides these,the mechanism for the influence of the particle size and carbon coating on the electrochemical property of LiFePO_(4)material was discussed in detail.
[1]Tarascon JM,Arm and M.Issues and challenges fac ingrechargeab le lith ium batteries[J].Nature,2001,414:359~367.
[2]Padh i A K,Nan jundaswamy K S,Goodenough J B,etal.Phospho-olivines as positive electrode m aterials forrechargeab le lith ium batteries[J].Journal of the E lec-trochem ical Soc iety,1997,144(4):1 188~1 194.
[3]Sylvain Franger,Carole Bourbon,Carole Bourbon,etal.Comparison between d ifferent L iFePO4synthesisroutes and the ir influence on its physico-chem ical prop-erties[J].Journal of Power Sources,2003,(119~121):252~257.
[4]Shoufeng Yang,Peter Y,Zavalij,et al.Hydrotherm alsynthesis of lith ium iron phosphate cathodes[J].E lec-trochem istry Commun ications,2001,3:505~508.
[5]L iao X Z,M a Z F,He Y S,et al.E lectrochem ical be-havior of L iFePO4/C cathode m aterial for rechargeab lelith ium batteries[J].Journal of the E lectrochem ical So-c iety,2005,152(10):A1969~A1973.
[6]Sh igeh isa Tajim i,Yosuke Ikeda,Kazuyosh i Uem atsu,et al.Enhanced perform ance of L iFePO4prepared byhydrotherm al reaction[J].Solid State Ion ics,2004,(175):287~290.
[7]Takahash i M,Tob ish im a S,Take i K,et al.Reactionbehavior of L iFePO4as a cathode m aterial for recharge-ab le lith ium batteries[J].Solid State Ion ics,2002,(148):283~289.
[8]B rian L Cush ing,John B Goodenough.Influence of car-bon coating on the perform ance of a L iMn0.5N i0.5O2cath-od[J].Solid State Ion ics,2002,(4):1487~1493.
[9]SH I Zh i-cong(施志聪),LI Chen(李晨),YANG Yong(杨勇).The electrochem ical perform ance stud ies onnovel L iFePO4cathode m aterials for L i-ion batteries[J].E lectrochem istry(in Ch inese),2003,9(1):9~14.
